Long-Term Effects of Clipping and Nitrogen Management in Turfgrass on Soil Organic Carbon and Nitrogen Dynamics:
The CENTURY Model Simulation. (C05-qian838458-oral)
Authors:
Y.L. Qian* - Colorado State University
W. Bandaranayake - Colorado State University W.J. Parton - Colorado State University
B. Mecham - Northern Colorado Water Conservancy District M.A. Harivandi - Univ. of Calif.
A.R. Mosier - USDA-ARS
Abstract:
Experiments to document the long-term effects of turfgrass management on nitrogen (N) requirement, soil organic carbon (SOC) and soil organic nitrogen (SON) are difficult and costly and therefore few.
The CENTURY ecosystem model offers an opportunity to study long-term effects of turfgrass clipping management on biomass production, N requirements, SOC and SON content, and N leaching through computer simulation. In this study, the model was verified by comparing CENTURY-predicted
Kentucky bluegrass clipping yields with field-measured clipping yields. Long-term simulations were done for Kentucky bluegrass grown under home lawn conditions on a clay loam soil in Colorado. The model predicted that compared with clipping-removed management, returning clippings for 10-50 years would increase soil C sequestration by 11-59 % and nitrogen sequestration by 12-78 %. The
CENTURY model was further used to generate optimal N fertilization rates as a function of turfgrass age. As the age of a turf ecosystem increases, N application rate needs to be reduced due to the greater amounts of N mineralized and recycled from SOM. Returning grass clippings to the turf/soil ecosystem can reduce N requirements by 25% from 1 to 10 years after turf establishment, by 33% 11-25 years after establishment, by 50% 25-50 years after establishment, and by 60% thereafter.
Speaker Information: Yaling Qian, Colorado State University, Dept. of Hort. and L.A. Colorado State Univ., Fort Collins, CO 80523; Phone: 970-491-7079; E-mail: [email protected]
Session Information: Monday, November 3, 2003, 7:55 AM-10:30 AM Presentation Start: 9:15 AM
Keywords: Turfgrass; soil organic carbon; soil organic nitrogen; biomass
